Hi,
I am slowly welding my 1974 412LE 4-door sedan back together. Once the bodywork is done, it'll be time for the mechanics. The FI engine is great but the gearbox slips out of 2nd gear.
I have found a NOS 411 gearbox and want to know what (if any) differences there were between models (411-412 sedan-variant).
Does anyone have any information?
thanks in advance
Kieron
411/412 gearbox - differences?
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raygreenwood
- Posts: 11906
- Joined: Wed Jan 22, 2003 12:01 am
The tpe 4 gear box is...and is not...like other VW transmissions. There are two main reasons...in order...that a 004 gearbox pops out of gear.
(1) Engine driveline bushings and alignment. What is actually happening is that the tranny is "shifting" itself out of gear. This is THE most common issue. Because the entire driveline is suspended by the middle support bar over bell housing/engine jont.....the tail cone bushing and the rear hanger bar bushings are simply bumpers to arrest excessive rocking movement longitudinally. By that I mean the tail cone moving up and down. The bumper bushing on that tail cone must be exactly centered and have no more than about 1.5mm of play all the way around it. If this bushings comes hard against any area of the socket in the rear crossmember....it causes ineterference and wear in the shifter circuit and tranmission.
Likewise
....if the center bushings on the rear hanger bar are in por shape...or if the bar and engine position are out of adjustment....and the bushings are either over compressed....or over extended....the entire drivlein package pivots around the center hanger bar....lifting or depressing the tailcone...and causing the alignment problem mentioned above.
Again....likewise....if the center hanger bushings are torn or worn....the whole drive train package can "slide" fore and aft....tearing up the rear hanger bushings and bring teh tail cone bushing bracket up hard against the rear suspension cross member.
What this all means....is that naytime time teh rear tail cone is misaligned for nay of these reasons...or moves excessivly....it changes the fore and aft rod throd of the shift rod...and/or changes the degree of arc of the floating coupling between the shift rod and transmission. This can and will cause the shifter adjustment to be incorrecet and cause popping out of gear.
Also make sure your front sifter bushing is correct and make sure the round plastic shift rod support plate at the end of the tunnnel is in place.
(2) The other thing is worn shift rods or detents like in any other transmission. This is actually rare. Since the rods are case hardened and the spring detents are softer, it can be a worn detent. The detents are accessable and removable from the outside of the case in just minutes. It can be as simple as simply pulling a less used detent out with a magnet and swapping it with another from one of the other shift rods. Or...simply putting a stronger spring into it.
The 411 early transmissions had a slightly different synchro set-up. I will have to consult the book to see the date cut-off. All of the later boxes had an extra synchro.
The classic 411 tranny had a differnt slave cylinder (19mm) and a totally different bell housing and throwout lever. Ray
(1) Engine driveline bushings and alignment. What is actually happening is that the tranny is "shifting" itself out of gear. This is THE most common issue. Because the entire driveline is suspended by the middle support bar over bell housing/engine jont.....the tail cone bushing and the rear hanger bar bushings are simply bumpers to arrest excessive rocking movement longitudinally. By that I mean the tail cone moving up and down. The bumper bushing on that tail cone must be exactly centered and have no more than about 1.5mm of play all the way around it. If this bushings comes hard against any area of the socket in the rear crossmember....it causes ineterference and wear in the shifter circuit and tranmission.
Likewise
....if the center bushings on the rear hanger bar are in por shape...or if the bar and engine position are out of adjustment....and the bushings are either over compressed....or over extended....the entire drivlein package pivots around the center hanger bar....lifting or depressing the tailcone...and causing the alignment problem mentioned above.
Again....likewise....if the center hanger bushings are torn or worn....the whole drive train package can "slide" fore and aft....tearing up the rear hanger bushings and bring teh tail cone bushing bracket up hard against the rear suspension cross member.
What this all means....is that naytime time teh rear tail cone is misaligned for nay of these reasons...or moves excessivly....it changes the fore and aft rod throd of the shift rod...and/or changes the degree of arc of the floating coupling between the shift rod and transmission. This can and will cause the shifter adjustment to be incorrecet and cause popping out of gear.
Also make sure your front sifter bushing is correct and make sure the round plastic shift rod support plate at the end of the tunnnel is in place.
(2) The other thing is worn shift rods or detents like in any other transmission. This is actually rare. Since the rods are case hardened and the spring detents are softer, it can be a worn detent. The detents are accessable and removable from the outside of the case in just minutes. It can be as simple as simply pulling a less used detent out with a magnet and swapping it with another from one of the other shift rods. Or...simply putting a stronger spring into it.
The 411 early transmissions had a slightly different synchro set-up. I will have to consult the book to see the date cut-off. All of the later boxes had an extra synchro.
The classic 411 tranny had a differnt slave cylinder (19mm) and a totally different bell housing and throwout lever. Ray
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kps70
- Posts: 77
- Joined: Tue Jan 16, 2007 2:00 pm
Wow - loads of information. Thanks!
What you're basically saying then is that I can go to all the trouble of putting in a brand new gearbox and due to ecessive play elsewhere, the problem will persist? mmm I'll check the basics first but I might get the box anyway as it is going cheap and it is NOS! I'm just waiting for the guy to give me some code numbers to see if they match mine. Is there a published list of 411/412 gearbox code numbers?
thanks again
Kieron
What you're basically saying then is that I can go to all the trouble of putting in a brand new gearbox and due to ecessive play elsewhere, the problem will persist? mmm I'll check the basics first but I might get the box anyway as it is going cheap and it is NOS! I'm just waiting for the guy to give me some code numbers to see if they match mine. Is there a published list of 411/412 gearbox code numbers?
thanks again
Kieron
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func412
- Posts: 506
- Joined: Sun Apr 03, 2005 10:55 am
Type 4 Variant has always had 3,91 final drive (toothed 11/43), as well as the limousine years -71 and -72 until may or june (there is some dissimilair information available from different sources about the month). The transmission code is FC.
Limousines -69 and -70 came with 3,73 final drive (toothed 11/41) with transmission code FA and after may/june -72 was the final drive also 3,73 in transmission coded FB.
In addition to these transmissions there has been a special transmission fon Variant coded FE which is toothed 10/39, so the final drive is almost the same as other Variant transmissions (3,90).
Limousines -69 and -70 came with 3,73 final drive (toothed 11/41) with transmission code FA and after may/june -72 was the final drive also 3,73 in transmission coded FB.
In addition to these transmissions there has been a special transmission fon Variant coded FE which is toothed 10/39, so the final drive is almost the same as other Variant transmissions (3,90).
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raygreenwood
- Posts: 11906
- Joined: Wed Jan 22, 2003 12:01 am
I always say...buy any 411 412 004 gearbox you can find and afford. If not a full spare...parts are always welcome.
The sad part is that there is only reference to driveline alignment adjustments in one VW shop book. In that manual...the tranny info and the heater info are the ONLY useful information. That is the Clymer manual.
It took me YEARS to figure out shifting issues that were really drivetrain alignment. These problems really get started when the hanger bushings over the tranny and the rear hanger bar center bushings start to go bad.
When they do...the position of the tranny and engine sags....misaligning the rear slip coupling. Ray
The sad part is that there is only reference to driveline alignment adjustments in one VW shop book. In that manual...the tranny info and the heater info are the ONLY useful information. That is the Clymer manual.
It took me YEARS to figure out shifting issues that were really drivetrain alignment. These problems really get started when the hanger bushings over the tranny and the rear hanger bar center bushings start to go bad.
When they do...the position of the tranny and engine sags....misaligning the rear slip coupling. Ray